The present invention relates to an apparatus for reducing the vibrations of an engine, which are produced while the engine is idling.
Internal combustion engines produce torque variations or fluctuations by the combustion strokes of respective engine cylinders during operation, and such torque variations or fluctuations result in engine vibrations. The vibrations of the engine are transmitted to the vehicle body of a motor vehicle on which the engine is mounted, generating noises that make the driver and passengers in the passenger compartment uncomfortable.
One practical solution has been to employ a balance shaft parallel to the crankshaft of the engine. The balance shaft is rotated about its own axis in ganged relation to the crankshaft for canceling out variations of the engine torque. While the balance shaft is effective in reducing the engine vibration, a complex mechanism is necessary to rotate the balance shaft in synchronism with the crankshaft, and the balance shaft and such a mechanism make the engine heavy.
Another proposal is a vehicle generator control apparatus disclosed in Japanese Laid-Open Patent Publication No. 63(1988)-167640. The disclosed vehicle generator control apparatus controls the consumption of electric energy generated by a generator which is driven by an engine, based on the rotational speed of the engine. Variations or fluctuations in the rotational speed of the engine while it is idling are suppressed by placing the engine under a load depending on the rotational speed of the engine. In order to prevent the rotational speed of the engine from increasing, the electric current from the generator is supplied to a resistor, which consumes the electric current as heat. Therefore, the generated electric energy is wasted.